Digital deflection control system in projection TV

Abstract

A digital deflection control system in a projection TV is provided which digitally integrates the configuration for converting the digital horizontal deflection signal outputted from the DCS into an analog signal to be applied to the deflection coil as an input, thereby reducing the production cost and realizing small-size product. The digital deflection control system includes an EEPROM for storing vertical and horizontal deflection seed data for R, G, B color signals, a CPU for loading each seed data from the EEPROM and performing the first interpolation for the horizontal deflection data, a digital conversion circuit for performing the second interpolation for the vertical deflection data among the data first-interpolated by the CPU, a digital deflection control for performing the third interpolation for the horizontal deflection data among the data second-interpolated by the digital conversion circuit, a D/A converter for outputting the data third-interpolated by the digital deflection control as an analog signal in the form of step wave, and a filter for removing high frequency component from the signal in step waveform outputted from the D/A converter.

What is claimed is: 
     
       1. A digital deflection control system in a projection TV, the system comprising: an EEPROM for storing vertical and horizontal deflection seed data for R, G, B color signals;   a CPU for loading each seed data from the EEPROM and performing the first interpolation for the horizontal deflection data;   a digital conversion circuit for performing the second interpolation for the vertical deflection data among the data first-interpolated by the CPU;   a digital deflection control for performing the third interpolation for the horizontal deflection data among the data second-interpolated by the digital conversion circuit;   a D/A converter for outputting the data third-interpolated by the digital deflection control as an analog signal in the form of step wave; and   a filter for removing high frequency component from the signal in step waveform outputted from the D/A converter.   
     
     
       2. The system as claimed in the claim 1, wherein the digital deflection control comprises: a buffer for temporarily storing horizontal signal data for one horizontal line, second-interpolated by the digital conversion circuit;   a subtracter for obtaining the difference (An+1)-An between two pieces of horizontal signal data An+1 and An for one horizontal line, sequentially inputted from the buffer, and outputting the subtraction result;   a divider for dividing the difference obtained by the subtracter by a predetermined divisor;   a shift register for storing the result value obtained by the divider, and performing shifting operation in synchronization with a clock signal at which following horizontal signal data An+2 is inputted; and   an adder for adding horizontal signal data inputted from the digital conversion circuit at every specific clock to interpolation data stored in the shift register.   
     
     
       3. The system as claimed in claim 2, wherein the divisor is 4 or 8.